Methanedisulfonic acid is also known as methionic acid, methylenedisulfonic acid, methyl disulfonic acid or methane-disulfonic acid and has English names of Methanedisulfonic acid (MDSA), Methionic acid or Methanedisulphonic acid, of which the CB Number is CB 9742754, molecular formula is CH4O6S2, the molecular weight is 176.17, CAS is 503-40-2, and the structural formula is:
Methanedisulfonic acid is an alkyl disulfonic acid with the shortest carbon chain, has a variety of special physical and chemical properties, and is widely used in electronics, surface treatment, medicine, battery and other industries.
U.S. Pat. No. 2,492,938, U.S. Pat. No. 2,493,038 reported a method for preparing the compound by the reaction of “methane with sulfur trioxide”. The reaction process is shown as follows:
However, the method finally obtains a mixture of several acids such as methanedisulfonic acid, methanesulfonic acid, sulfuric acid and so on, which is quite difficult to be separated. Thus, it is very difficult to obtain methanedisulfonic acid that meets the quality requirements.
U.S. Pat. No. 2,842,589 disclosed a preparation of methanedisulfonic acid by the reaction of “methanesulfonic acid with sulfur trioxide”:
The method is similar as the method utilizing the reaction of “methane with sulfur trioxide”, and also has a problem of purification.
Sartori, Pete et al. (Sartori, Peter; Jueschke, Ralf; Boese, Roland; Blaeser, Dieter; Zeitschrift fuer Naturforschung, B; Chemical Sciences; vol. 49; nb. 11 (1994); p. 1467-1472) reported a method for preparing methanedisulfonic acid by the hydrolysis of “methanedisulfonyl chloride”, and the reaction formula is shown as follows:
However, the preparation of dimethylsulfamoyl chloride is more difficult than that of methanedisulfonic acid, and thus this method cannot be industrialized.
Goldwhite, H. et al. (Tetrahedron; vol. 21; 1965; p. 2743-2747) reported a method for preparing methanedisulfonic acid from sodium methanedisulfonate as the raw material by a two-step reaction, the overall reaction of which is shown as follows:
The method additionally has a reaction for preparing sodium methanedisulfonate itself, and thus is actually a three-step reaction. The method has relatively more steps, the purification process is complex, the total yield is low, and there is heavy metal pollution in the procedure. Therefore, it is not conducive to industrial production. The method disclosed in US Patent Application US 2006155142 is similar as the above method. Likewise, CN Patent ZL 95101622.9 disclosed a method for preparing “sodium methanedisulfonate”.
In the method for preparing methanedisulfonic acid, it was proposed that “it may be converted by its sodium or potassium salt”, but no specific method is known. The inventor tried to prepare methanedisulfonic acid from its sodium or potassium salt by a method of ion exchange, and found that only a mixture of methanedisulfonic acid and the salt thereof was obtained, and the mixture is difficult to be further separated. Moreover, the concentration of the mixture was very low, such that it required a large quantity of energy for a suitable concentration. Therefore, it still requires further research and exploration on how to easily produce high-quality methanedisulfonic acid with a low-cost, high-yield and environmental friendly manner.